The present invention relates to telephone switches, and in particular to the attachment of devices to telephone switches and proper configuration of such devices.
Telephone switches are used to connect devices and to connect multiple devices together so that they can exchange information. The most common form of device is a telephone. The switches allow users of the telephones to talk to each other by connecting them via various communications lines. Private switches are used in many buildings to make connections between devices attached to the same switch, and to provide external connections to other switches outside the building. There are many different types of switches, and each talk to the devices in different ways. Most new switches are digital in nature, and require the device to xe2x80x9ctalkxe2x80x9d to it with a predetermined bit pattern. The bit pattern may be different for each switch. In addition, each switch may be configured with multiple electronic circuit cards containing connectors for making the actual connection to wires attached to the device. When wiring a building to provide this communication line between the devices and the switches, the technician had to know what type of switch each device was connected to, and the type of card in the switch. The devices either had to be a certain type, or had to have software loaded into them so they could both understand the bit stream provided by the card in the switch, and so that they could respond with the proper bit stream.
With potentially thousands of telephones coupled to a single switch, and many different lines, it was difficult to keep track of what switch and card was attached to what wire. The configuration of the switch and line card had to be manually looked up, and then manually entered into the attaching device. There was much room for error. When error occurred, the device was not able to be used until it was corrected. In some instances, a device configuration program would query a user, or installer for line specific data. The user/installer would then ask a telecom administrator for the corresponding information, usually in person, or through the use of a separate, already working telephone. The telecom administrator would then have to log into the switch and run a few administration programs to look up the line configuration data. This data would then be conveyed back to the user/installer, who would have to manually enter the data into some type of user interface of the configuration program for the device. For devices, such as a digital telephone, this could involve a sequence of touchpad keys that usually had no obvious logical significance, leading to potential error.
There is a need to simplify the connecting of telephones and other digital devices to switches. There is a need for a simple way of connecting devices to phone lines without requiring detailed knowledge of the switch and card. There is a need for further determining the proper format of digital bit stream with which to communicate with the switch without such detailed knowledge. There is yet a further need to easily determine the capabilities of the phone lines to which devices are connected without prior detailed knowledge of the configuration of the switch.
A device that attaches to phone lines automatically determines both the type of switch to which is connected, and the type of line card in the switch providing that connection. In addition, device functions and data types supported by the switch and line card are automatically determined, providing a fully automatically configurable device.
In one embodiment of the invention, the device contains programming that monitors polling messages provided by the switch and line card. The polling messages from the different combinations of switches and line cards each have the same information content. However, the polling messages from each potential combination of switch and line card have a slightly different format, which the device uses to identify the switch and line card to which it is attached. The devices switch between two different flow control types supported by the different line cards, while listening for the polling messages. If a message is not received while using a first flow control type, the second is used.
The type of data that the phone lines carry is automatically determined by either knowing that one particular switch and line card provide voice and data on both lines of a connection, or by prompting the switch for a keymap download on each line. The type of keymap download received, such as one containing a DTM key, indicates that both voice and data may be transmitted and received. If no DTM key is received, each line defaults to a predetermined one of voice or data.
Automatically configuring devices without need for complex and error prone installation greatly simplifies and speeds up accurate installation of devices in a switched network. Further, it provides the ability to take full advantage of all the functions supported by the switch to which devices are connected. Third parties can also easily design devices for attaching automatically to the switches.